Effect of different tumor types on resting energy expenditure.

The purpose of this study was to investigate whether the presence of a malignant tumor influences energy metabolism of the host. Resting energy expenditure (REE) was measured in 104 gastric and colorectal (GCR) cancer patients and in 47 non-small cell lung cancer patients and was compared with REE values in 40 healthy controls. REE expressed per kilogram of fat-free mass (FFM) in lung cancer patients was elevated, in comparison with healthy controls (33.6 +/- 4.6 and 29.6 +/- 2.9 kcal, respectively; P less than 0.001), in contrast to REE/FFM in GCR cancer patients, which showed no difference, compared with these controls (29.8 +/- 4.3 kcal). In 47 patients with GCR cancer and in 14 patients with lung cancer, REE was also determined after tumor resection. REE in GCR cancer patients measured 1.5 years after tumor resection showed a small but significant increase. No differences were observed between GCR cancer patients with or without signs of tumor recurrence. REE in lung cancer patients with no signs of tumor recurrence measured 1 year after tumor resection had a significant decrease in REE (REE/FFM, -6.8%; P less than 0.05), while patients who had evidence of tumor recurrence showed no change in REE or even an increase. After curative surgery REE returned to a normal level in the lung cancer patients. These results suggest that tumor type is a major determinant of an increased energy expenditure in cancer patients.